1. Field of the Invention
The present invention relates to a perforating apparatus, sheet processing apparatus, and image forming apparatus for perforating sheet material when conducting finishing such as binding of sheet material such as paper that has undergone image formation processing.
2. Description of the Background Art
Image forming apparatuses such as copiers, printers or fax machines, as well as printing presses can output images by transferring to a recording sheet such as paper visible images such toner images that have been carried on a latent image carrier. Other than when discharging in order from the image forming apparatus onto the discharge tray, the recording sheets may be transported to a finisher that perforates for filing, or conducts finishing such as printing, adding information, or subdividing into sheet groups.
Many finishers are used by connecting to the recording sheet discharge position of the image forming apparatus, and, for example, in addition to perforating for filing, the recording sheets are transported to inside the finisher, undergo finishing such as binding, and are discharged. One of the reasons that perforating is conducted first is that when conducting post-processing such as binding, the staples used in binding interfere and make perforation difficult.
When perforating, punch holes are formed on the predetermined edge of the transported recording sheets, but there are many types of perforation, and, for example, 2-hole, 3-hole and 4-hole perforation are representative types often seen in Japan and Europe. Moreover, in contrast to the punch hole diameters of φ6.5 for 2-hole perforation in Japan, φ8 may be selected for 2-hole and 3-hole perforation in the North America. φ6.5 may be selected for 4-hole perforation in Europe, and there are 4-hole perforations in Northern Europe that do not have equivalent spacing. Further, in addition to these formats, there are also multiple hole perforations for binders and the like.
Meanwhile, A4 and A3 size recording sheets are used as the recording sheet format for perforation in Japan and Europe, but in contrast, legal size recording sheets are often used in North America, and even with the same 2-hole and 3-hole perforation, the positions may differ between Japan, Europe and North America.
In the past, for example, Japan Patent Application Laid-open No. 2002-128385 (paragraph [0017] disclosed a configuration that addresses differing punch hole perforation positions and achieves various perforation formats by providing in a single perforation unit multi-stage punches that correspond to 2-hole and 3-hole uses and the like, and combines a main drive side and supplementary drive side used as the drive system of these punches.
If the number of punch holes and perforation position have been determined, perforation can be handled using a configuration like that disclosed in the above mentioned Japan Patent Application Laid-open No. 2002-128385, but, for example, if rather than a general user, the user is a book binder who receives many requests from clients desiring punch hole and perforation positions that differ from the predetermined format, when the perforating apparatus with a preset structure does not correspond to the desired format, it is necessary to replace that apparatus with a special order perforating apparatus that corresponds to the desired format. However, a worker may not be trained in the configuration, and may have difficulty on his own in the assembly operation for removing the perforating apparatus from the image forming apparatus and replacing with a new perforating apparatus, and a service technician may need to conduct the replacement operation. Therefore, operations in the book binding process may have to be temporarily suspended.
Moreover, when perforating with a punch hole, after the lateral registration has been adjusted to correct for discrepancies in the width direction, which is equivalent to the direction perpendicular to the direction of transport of the recording sheet, to execute the perforation operation, highly precise determination of the perforation position of the recording sheet in the width direction is to be conducted. Therefore, when incorporating the replacement perforating apparatus into the post-processing apparatus main unit, the replacement operation is not simple even for a service technician because incorporation into the drive unit requires precision.
Meanwhile, the punch drive and the drive mechanism for the aforementioned lateral registration adjustment are respectively mounted in the perforating apparatus, but the fact that drive mechanisms are provided in every perforating apparatus makes the high cost of the perforating apparatus, especially the cost of parts, a concern.
When replacing the existing perforating apparatus with a perforating apparatus for special order parts, the type of perforating apparatus replaced is confirmed and the conditions must be set corresponding to this type, but if the user sets the conditions, improper operation or tedious operation become problems. There is also the problem that the perforation operation cannot be conducted unless it is verified whether the perforating apparatus targeted for replacement has undergone position determination to the specified position. Therefore, these types of operations constrain the user, and there is the concern of placing a large burden on the user.